#include<iostream>
#include<vector>
#include<queue>
#include<cstring>
#include<cmath>
#include<map>
#include<set>
#include<cstdio>
#include<algorithm>
#define debug(a) cout<<#a<<"="<<a<<endl;
using namespace std;
const int maxn=1e6+100;
typedef long long LL;
const LL mod=1e9+7;
inline LL read(){LL x=0,f=1;char ch=getchar();	while (!isdigit(ch)){if (ch=='-') f=-1;ch=getchar();}while (isdigit(ch)){x=x*10+ch-48;ch=getchar();}
return x*f;}
LL dp[maxn];
LL ksm(LL a,LL k){
    LL res=1;
    while(k>0){
        if(k&1) res=res*a%mod;
        k>>=1;
        a=a*a%mod;
    }
    return res%mod;
}
int main(void)
{
  cin.tie(0);std::ios::sync_with_stdio(false);
  LL n;cin>>n;
  dp[0]=0;dp[1]=0;dp[2]=1;
  for(LL i=3;i<=n;i++){
    dp[i]=(dp[i-1]*25%mod+ksm(26,i-1)%mod-ksm(25,i-1)%mod+mod)%mod;
  }
  LL sum=0;
  for(LL i=1;i<=n;i++){
    sum=(sum%mod+dp[i]%mod)%mod;
  }
  cout<<sum<<"\n";
return 0;
}
